It is frequently necessary for a medical practitioner to inspect the colon or rectum of a patient. This procedure is commonly conducted with a sigmoidoscope which in the past consisted of a metal tube or speculum adapted at one end for insertion into the rectum of a patient and adapted at the other end for connection with a manifold. The manifold was provided with an observation window, a rubber bulb insufflator connectable via a spigot to the manifold and communicating with the interior of the speculum whereby the bowel may be pressurised, and an illuminator with which at least a portion of the bowel interior may be illuminated during examination. In the past after use and before reuse on a subsequent patient, the metal tube was sterilised. Subsequently there were developed sigmoidoscopes in which parts coming in contact with the patient were designed to be thrown away after use to save the time and expense of cleaning and sterilising.
Presently used sigmoidoscopes employ a disposable speculum in the form of a hollow, light transmissive, plastic rube. The disposable speculum is purchased in a clean or sterile condition sealed in a bag together with a disposable obturator adapted for use with the speculum. In use the disposable speculum is coupled to a non-disposable fibre optic head which has a hinged window through which an obturator or biopsy instrument may be inserted and removed coaxially through the interior of the speculum.
A light source is operatively coupled with the speculum via the fibre optic head so as to illuminate a circumferential end edge of the speculum via fibre optics whereby light from the illumination means may be directed through the wall of the speculum into the anal canal, bowel, or other body cavity under examination. The fibre optic head is also provided with a spigot for connection, for example via a flexible communicating tube, to an insufflation bulb with which the bowel may be insufflated with air. After use the obturator is discarded.
Upon conclusion of an examination the inexpensive plastic disposable speculum is also disconnected from the fibre optic head and disposed of. The fibre optic head together with the hinged window mounted thereto and, fibre optic illumination means costs in excess of $750 and are retained for use with another speculum. The insufflation bulb may be disconnected between uses but commonly remains connected to the fibre optic head.
Although the invention will be herein described with reference to sigmoidoscopy, it will be understood that the invention is equally applicable to other forms of endoscopy which involve inflation of an internal cavity to be examined and is not limited to instruments for use in bowel examination.
The present inventor has discovered a previously unrecognised potential for cross-infection from sigmoidoscopy.